### 6 Two and three bolometer chopping

It is possible to chop between two or three bolometers on the array, the main benefit being more time spent on-source during the observation. The reduction of these data is very similar to the single bolometer method shown in the preceeding section. The only recognizable difference is that scucat will produce a concatenated output file for each bolometer. For example, if data were taken simultaneously with the long-wavelength array pixels h7 and h9 and the specified output file is source1 then files source1_h7.sdf and source1_h9.sdf will result.

The most robust method of reducing these data is to observe a planet, such as Mars, in exactly the same way and then to calibrate each bolometer separately into flux units. The coadded result and its statistical uncertainty can then be calculated with standard formulae.